Abstract

ALARCON, Carlos M.; CLAVIJO-TORRES, Jairo; MANTILLA-FIGUEROA, Luis C  and  RODRIGUEZ, Juan Guillermo. A new proposal on ages of the sedimentary record of Bocas and Jordan formations and their relationship with the development of the magmatic activity of the Santander Plutonic Group (Eastern Cordillera, Colombia). Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2020, vol.44, n.173, pp.1137-1151.  Epub July 07, 2021. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.1208.

The geological information of the Jurassic record in the Northern Andes of Colombia indicates that during this time, magmatic activity, metamorphism, and sedimentation developed simultaneously. In the Santander Massif (Eastern Cordillera of Colombia), vestiges of this magmatic activity can be recognized by the presence of igneous plutonic bodies (Santander Plutonic Group). New paleontological studies in rocks from the sedimentary record of the Bocas Formation allowed for preliminary identification of conchostracans species: Shipingia hebaozhaiensis, Euestheria buravasi, and Laxitextella multireticulata of the Late Triassic age. U/Pb geochronology in ignimbrite and rhyolitic tuff of the Jordan Formation yielded ages of 199.37 ± 0.34 Ma and 198.49 ± 0.33 Ma defining an Early Jurassic age for this unit. These results indicate that the lithological record of volcanic origin within the Jordan Formation is contemporary with the development and genesis of the Santander Plutonic Group (age ~ 202-195 Ma).

Keywords : Northern Andes; Santander Massif; Jordan Formation; Bocas Formation; Santander Plutonic Group.

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